Universal bellhousing, system and method therefore

ABSTRACT

A universal bellhousing which may be adapted to a variety of automotive engine and transmission combinations and method of making the same is disclosed. The bellhousing is made by spin forming a sheet of material and welding a transmission plate onto the cone. The cone and transmission plate are indexed to mount to a specified engine-transmission combination.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/032,700 filed on Sep. 20, 2013, now U.S. Pat. No. 9,360,100, which isa divisional application of U.S. patent application Ser. No. 12/258,912,now U.S. Pat. No. 8,561,283, which claims priority to U.S. ProvisionalApplication No. 60/983,347 filed on Oct. 29, 2007. The disclosure ofthese applications are hereby incorporated by reference in theirentirety.

TECHNICAL FIELD

Exemplary embodiments of the present invention relate generally to anapparatus to connect an engine to a transmission and a method offabricating said apparatus.

BACKGROUND

Transferring power from a rotating engine or motor to a transmission orother implement requires an attachment mechanism to absorb therotational torque differential between the engine and the desiredtransmission or implement. The attachment maintains a specificrelationship of the components to prevent unwanted loss of energy fromfriction associated with misalignment of the rotating shaft from themotor with a transmission or other component. Additional considerationis given for the forces generated from the environment the assembly isto be employed. In an internal combustion engine, the area between theengine and the transmission is commonly called a bellhousing.Historically Automobile, Truck, and Implement Manufacturers haveprovided their bellhousings from several processes; namely metalcasting; metal pressing using dies and presses and occasionally a hydroform pressing method requiring a less costly form of die.

A bellhousing also provides an area for controlling power transfer fromthe motor to the attachment to it.

Inside the bellhousing a clutching mechanism and often a starting systemfor the motor is placed. The bellhousing encapsulates these mechanismsprotecting the components from the outside environment and hopefullycontains any failure of the components within the bellhousing.

Bellhousings are attached to the motor with taps and commonly to thetransmission or implement with taps. The pattern of the tapped holesvaries from manufacturer to manufacture and from motor type to motortype as well as transmission type to transmission type. Additionalvariations occur within subgroups from above to accommodate theclutching and starting systems required for each application.Manufacturers most often design and build a casting from aluminum oriron for each application. The process requires a large commitment ofcapital and time designing the molds. They can only justify the largeinitial startup costs through the economics of mass production.

The manufacturer is faced with a tradeoff of weight versus strength whenselecting either aluminum or steel. In the marketplace there hasdeveloped a need for a lighter weight steel bellhousing to accommodatethe manufacturer's production needs. New high torque engines createstresses that cause failure of the traditional cast bellhousing.

In areas of motor sports all the circumstances above; flexibility ofapplication; strength versus weight; production cost; and safety areequally important. Most motor-sport sanctioning bodies are now requiringbellhousings capable of containing all the components within thebellhousing in the event of a failure. Most require a steel bellhousing.Modern engines are producing torque in excess of the design parametersof traditional bellhousing. The consumer desires an affordable and safebellhousing that can be tailored to multiple combinations common intheir competition. This market is not economically viable fortraditional mass production methods since the price per piece is notsufficiently off set by production numbers.

Automotive restoration and modification has demands similar to the motorsport consumer. The flexibility and strength of the spun bellhousingenables combinations of almost any imaginable at a reasonable cost.Likewise, all high torque, limited production applications of rotatingenergy from a motor to an attachment will benefit from the lower perunit cost of spun bellhousing.

BRIEF SUMMARY OF THE INVENTION

A summary of certain embodiments of the invention disclosed herein isincluded below. It should be understood that these aspects are presentedfor purposes of providing the reader with summary of these embodimentsand that these aspects are not intended to limit the scope of thisdisclosure. Indeed, this disclosure may encompass a variety of aspectsthat may not be set forth below.

The present invention generally relates to an improved attachment,hereafter “bellhousing,” for use in rotating power transmission systems.The bellhousing is formed from a sheet of metal into a generally conedshaped housing having an integrally formed flange extending from thecone. A plate is attached onto the opposing end of the cone thatattaches to a transmission or other implement. This assembly is thenmachined and cut to accommodate any number of motor to transmission orimplement combinations.

The process reflects the latest in technological advances in metallurgyand metal spinning. When first introduced, modem high strength alloysexceeded the existing capabilities of traditional metal spinning. Recentimprovements in metal spinning now allow high strength alloys to beformed in a spin forming machine.

A spun bellhousing from a high strength alloy maintains its shape sincethe spin forming eliminates residual stress associated with traditionalpressing methods. The combination of modem alloys and high powerspinning machines eliminates the costly development of molds for castingor forms for pressing or hydro forming. The finished product isstronger, lighter, and more stable than traditional pressed or castattachments. The process allows short production runs decreasing perunit costs and the benefits of infinite flexibility. Modem spin formingand alloys provide a safer, stronger more stable product with fewercosts than the other processes.

The present invention generally relates to an improved bellhousing foruse in an automobile, the bellhousing being formed by spin forming asheet of metal into a generally cone shaped housing having an integrallyformed flange extending from the cone. A transmission plate is thenwelded onto the cone. Finally, the transmission plate and integrallyformed flange are shaped and cut to accommodate any of a number ofengine and transmission combinations.

The process of making such a bellhousing does not require thedevelopment of forms, such as those required for hydroforming orpressing, and may be formed from a steel plate, thereby increasing thesafety factor of the bellhousing. Additionally, a variety of engine andtransmission combinations may be used without expensive or weightyadapter plates between the bellhousing and engine or transmission. Thespin forming step also eliminates residual stress in the bellhousing,further increasing its safety qualities.

Again, the brief summary presented above is intended only to familiarizethe reader with certain aspects and contexts of embodiments of thepresent disclosure without limitation to the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

In addition to the features mentioned above, other aspects of thepresent invention will be readily apparent from the followingdescriptions of the drawings and exemplary embodiments, wherein likereference numerals across the several views refer to identical orequivalent features, and wherein:

FIG. 1 is a perspective view of the bellhousing according to a preferredembodiment;

FIG. 2 is a perspective view of the bellhousing from an opposite end;

FIG. 3 is an end view of the preferred embodiment;

FIG. 4 is a side view of the preferred embodiment;

FIG. 5A shows a method of forming the bellhousing by use of an internalspin forming machine;

FIG. 5B shows a method of forming the bellhousing by use of an externalspin forming machine; and

FIG. 6 shows the various steps in producing the bellhousing according tothe preferred embodiment.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT(S)

An embodiment of this invention is a universal bellhousing design andmanufacturing process that allows a small number of housing sizes to beconfigured to mate with a large number of engine and transmissionmodels. This is an important aspect of this invention as each engine andtransmission has a unique mounting pattern and size and thus wouldrequire separate tooling.

As shown in FIGS. 1-4, the bellhousing 10 generally comprises a cone 12,a flange 20, and a transmission plate 30. The flange 20 has a holepattern 24 corresponding to a mating surface on an engine. Thetransmission plate 30 also has a hole pattern 34 and a profile 32corresponding to a transmission. The cone 12 also features a number ofopenings 14 which allow the bellhousing 12 to fit about the enginetransmission interface while allowing access for the shifter cable andstarter. The arrangement of the openings 14, and the hole pattern 24 onthe flange 20 and hole pattern 34 on the transmission plate 30 are shownmerely by example, as each engine-transmission combination may requiredifferent shapes or arrangement of these features.

As previously discussed, there are different methods available for theconstruction of bellhousings. These methods include hydroforming,casting, or pressing. Each of these methods is not preferable for custommade bellhousings because of an increased startup cost as well aslimitations in the type of material which may be used.

The present invention contemplates the use of spin forming to form thebasic bellhousing shape. The process is generally shown in FIGS. 5A and5B, with the specific assembly process for the bellhousing shown in FIG.6.

FIGS. 5A and 5B show alternative methods of spin forming a sheet ofsteel into a cone for use in the bellhousing. FIG. 5A shows the use ofan internal type spin forming and FIG. 5B shows the use of an externaltype spin forming.

FIG. 5A shows internal-type spin forming. A sheet of steel 40 is placedonto the spinning machine 50 with the central axis 58 passing throughthe indexing hole 42. The sheet 40 is then secured by a support 60 andspun at a high speed. As the sheet 40 spins, a roller 56 exerts forcedownward onto the sheet 40 forcing it into the cavity 52. The sheet 40is shaped to the cavity 52 while leaving a flange 20 integrally formedabout the edge of the cavity 52.

External spin forming is generally shown in FIG. 5A. In this method, asheet of steel 40 is placed onto a spinning machine 50 atop a mandrel54. The central axis 58 passes through the indexing hole 42 and thesheet 40 is secured with a support 60. The sheet 40 is then spun at highspeed and a roller 56 forces the sheet about the mandrel 54. In thismanner, a cone shape is formed about the mandrel with a flange 20integrally formed with the cone 12. As shown in FIG. 5B, once the cone12 is formed, the flange 20 is not level to the cone 12. Therefore, aseparate step is required to level the flange 20 prior to finalmachining. This step could be performed by a press or other similarprocess known in the art.

As shown in FIG. 6, an exemplary embodiment of the process starts with asingle sheet 40 of steel, preferably ⅜″ for safety reasons.

Next, an indexing hole 42 is drilled through the center of the sheet 40;this hole 42 is preferably approximately 1″ in diameter and is used toalign the sheet 40 onto the spinning machine 50.

The sheet 40 may then be formed by spin forming into a cone 12 with anarrow end 16, a wide end 18, and a flange 20 extending from the wideend 18. The cone is defined by its height, diameter and angle of taper.

The cone 12 is next cut to a preferred height relative to the flange 20.This distance is determined by the precise specifications between theengine and transmission. Along with cutting the cone height, noncriticaloperations are also performed. The openings 14 are also cut and theprofile 22 of the flange is cut. These features are not held to thetight tolerances of the transmission and engine interfaces, and so maybe performed at this stage. The cuts are preferably performed by anautomated 5-axis laser cutter. Being automated, such as by computernumerical control (CNC), individual bellhousing profiles may be storedand retrieved according to production demands. The 5-axis laser cuttereliminates error due to moving the part and allows cuts to be made at avariety of positions and angles.

The transmission plate 30, already having a profile 32 and center hole36 for aligning with the transmission, is then welded onto the narrowend 16 of the cone 12. As with the flange profile 22, the transmissionprofile 32 is not required to be held to a tight tolerance. Therefore, anumber of transmission plates 30 corresponding to a variety of differenttransmissions may be cut before welding the transmission plate 30 to thebellhousing 10. The central hole 36 of the transmission plate 30 iswithin a tolerance (e.g., 0.1″) of the final dimension. This centralhole 36 is centered onto the cone 12, thereby ensuring concentricitybetween the flange 20 and transmission plate 30.

As a final step, the bellhousing 10 is moved to a table for precisionmachining. First, the transmission plate 30 and flange 20 are leveledrelative to one another to a precision tolerance (e.g., 0.001″). Thehole pattern 24 in the flange 20 is then cut, including precision fitdowels. The central hole 36 and hole pattern 34 of the transmissionplate 30 are also cut at this time, corresponding to the selectedtransmission. All of the operations in the final step are performed on asingle machine, thereby ensuring a precise tolerance (e.g., 0.001″).

As has been previously described, the method of forming the bellhousingallows for a variety of transmission and engine combinations to beassembled together through the use of a single bellhousing. It should beappreciated to those skilled in the art that alternative embodiments ofthe method of forming the bellhousing may also be used. For example, thecone may be formed by hydroforming, pressing, or casting. The remainingsteps would then be followed as described above in order to produce auniversal bellhousing.

Hydroforming is a process by which a form is pressed out of a sheet ofmetal by the use of hydraulic pressure. The sheet of metal is placedonto a flexible diaphragm and a male mold is pressed into the sheet.Hydraulic pressure provides the energy for deforming the sheet. Theflexible diaphragm provides resistance, thereby eliminating the need fora complimentary female mold. This type of metal forming is inexpensiveas it does not require complimentary molds and can be used for a varietyof shapes.

Pressing is a process by which a form is pressed out of a sheet of metalby a ram. The sheet of metal is placed onto a female die and a ramforces a male die onto the sheet. The sheet is then formed into theshape formed by the dies. This process is faster than hydraulicpressing, but requires more startup cost to form the dies.

Casting is a process of depositing molten metal into a form and thencooling the metal to set the form. The form must be designed for eachindividual bellhousing. This process requires a high startup cost, andis generally not suitable for use with high-strength steel. However, theprocess is preferred for large quantities of products.

Other alternative processes obvious to those in the field of art areconsidered to be included in this invention. The above description ismerely a single embodiment and limitations to the invention aredescribed in the patent. Any embodiment of the present invention mayinclude any of the optional or preferred features of the otherembodiments of the present invention. The exemplary embodiments hereindisclosed are not intended to be exhaustive or to unnecessarily limitthe scope of the invention. The exemplary embodiments were chosen anddescribed in order to explain the principles of the present invention sothat others skilled in the art may practice the invention. Having shownand described exemplary embodiments of the present invention, thoseskilled in the art will realize that many variations and modificationsmay be made to the described invention. Many of those variations andmodifications will provide the same result and fall within the spirit ofthe claimed invention. It is the intention, therefore, to limit theinvention only as indicated by the scope of the claims.

What is claimed is:
 1. A device for connecting an engine to atransmission, each having a mounting surface, the device comprising: astructure having an axis, a first end, and a second end, said first andsecond ends each having an opening and a wall extending between saidfirst and second ends wherein the openings are coaxial, the structureformed by deforming a spinning sheet of metal into a mold using aninternal spin forming process which asserts a force to the spinningsheet of material, such force applied along an inner surface of thesheet of material as it is formed; said structure having an outersurface that is free of strengthening ribs in an axial direction of thestructure; a spun formed flange formed from the spinning sheet andformed integrally with the structure, extending from the first endnormal to the axis; a transmission plate of a plurality ofinterchangeable transmission plates, affixed onto the second end of thestructure; and, a pattern of holes machined into each of the flange andthe transmission plate, the pattern of holes being indexed to an engineand transmission, respectively and the pattern of holes of thetransmission plate being disposed outwardly of the second end of thestructure.
 2. The device of claim 1, wherein the structure alsocomprises at least one opening formed along the wall of the structurebetween the first and second end.
 3. The device of claim 1, wherein thematerial is steel.
 4. The device of claim 1, wherein the material is ahigh strength alloy.
 5. The device of claim 1, wherein the transmissionplate is affixed by welding to the second end of the structure such thata first surface of the plate is essentially parallel to a surface of theflange formed at the first end of the structure.
 6. The device of claim1, wherein the tubular shape is a cone shape where the first end iswider in diameter than the second end.
 7. A device for connecting anengine to a transmission, each having a mounting surface, the devicecomprising: a structure having an axis, a first end, and a second end,said structure further comprising an opening at each of said first andsecond ends wherein the openings are coaxial, and a wall extendingbetween said first and second ends, the structure formed by deforming aspinning sheet of metal into a mold using an internal spin formingprocess which asserts a force to the spinning sheet of material, suchforce applied along an outer surface of the sheet of material as it isformed, said outer surface being free of strengthening ribs extending inan axial direction of the structure; a spun formed flange formed fromthe spinning sheet and formed integrally with the shape, extending fromthe first end of the shape normal to the axis; a transmission plate of aplurality of interchangeable transmission plates, affixed onto thesecond end of the structure; and a pattern of holes machined into eachof the flange and transmission plate, the pattern of holes of thetransmission plate being outward of the wall at the second end of thestructure, the pattern of holes being indexed to an engine andtransmission.
 8. The device of claim 7, wherein the structure alsocomprises at least one opening formed along the wall of the structurebetween the first and second end.
 9. The device of claim 7, wherein thematerial is steel.
 10. The device of claim 7, wherein the material is ahigh strength alloy.
 11. The device of claim 7, wherein the transmissionplate is affixed by welding to the second end of structure such that afirst surface of the plate is essentially parallel to a surface of theflange formed at the first end of the structure.
 12. The device of claim7, wherein the tubular shape is a cone shape where the first end iswider in diameter than the second end.